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Genetic, phenotypic and ecological divergence with gene flow at the Isthmus of Tehuantepec: the case of the azure‐crowned hummingbird ( Amazilia cyanocephala )
Author(s) -
RodríguezGómez Flor,
GutiérrezRodríguez Carla,
Ornelas Juan Francisco
Publication year - 2013
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.12093
Subject(s) - coalescent theory , gene flow , hummingbird , biology , genetic divergence , population , phylogeography , effective population size , evolutionary biology , range (aeronautics) , gene pool , ecology , genetic variation , zoology , genetic diversity , gene , genetics , phylogenetics , demography , materials science , sociology , composite material
Aim We test whether populations of the Mesoamerican azure‐crowned hummingbird, Amazilia cyanocephala (Trochilidae), located east and west of the Isthmus of Tehuantepec are genetically, morphologically and environmentally differentiated and examine the relative role of drift and selection in driving diversification. Location Mexico. Methods We sequenced the mitochondrial ATP ase‐6 and ATP ase‐8 genes and the control region of 130 individuals collected throughout the range of the species in Mexico. Population genetic methods and coalescent tests were used to reconstruct the phylogeography of the species. Morphological and niche variation between genetic groups of A. cyanocephala were assessed. Results The data revealed two genetic groups separated by the Isthmus of Tehuantepec in the late Pleistocene (49,300–75,800 years ago), with the split occurring in the presence of gene flow. Deviations from demographic equilibrium were detected for the two genetic groups, indicating more recent population expansions. Amazilia cyanocephala individuals from populations on either side of the Isthmus of Tehuantepec differed in morphology and were distributed in unique environmental space. A coalescent‐based test indicated that selection is driving the observed morphological differentiation. Main conclusions Our findings implicate the Isthmus of Tehuantepec as a permeable barrier driving recent diversification of A. cyanocephala in the presence of gene flow. The two A. cyanocephala mitochondrial DNA (mt DNA ) groups corresponding with morphological and environmental niche differences, in concert with the results of a coalescent‐based test, suggest that selection has been strong enough to counteract the effects of gene flow.